In the art of respiration devices respiratory masks which cover the nose and/or mouth of a human user are known. Known masks provide a continuous seal around the nasal and/or oral areas of the face, such that gas may be provided at positive pressure within the mask for consumption by the user. The uses for such masks range from high altitude breathing (i.e., aviation applications) to mining and fire fighting applications, to various medical diagnostic and therapeutic applications.
One requisite of such respiratory masks is to provide an effective seal against the user's face to prevent leakage of the gas being supplied. Commonly, in prior mask configurations, a good mask-to-face seal has been attained in many instances only with considerable discomfort for the user. A common complaint of a user of CPAP therapy is pressure sores caused by the mask about the nose and face and in particular in the nasal bridge region of the user. This problem is most crucial in those applications, especially medical applications, which require the user to wear such a mask continuously for hours or perhaps even days. In such situations, the user will not tolerate the mask for long durations and optimum therapeutic or diagnostic objectives may often not be achieved, or will be achieved with great difficulty and considerable user discomfort.
U.S. Pat. Nos. 5,243,971 and 6,112,746 are examples of prior art attempts to improve patient interfaces.